refcount_t type and corresponding API can protect refcounters from
accidental underflow and overflow and further use-after-free situations.
Signed-off-by: Xiyu Yang <[email protected]>
Signed-off-by: Xin Tan <[email protected]>
---
drivers/vhost/net.c | 14 ++++++++------
1 file changed, 8 insertions(+), 6 deletions(-)
diff --git a/drivers/vhost/net.c b/drivers/vhost/net.c
index 6414bd5741b8..e23150ca7d4c 100644
--- a/drivers/vhost/net.c
+++ b/drivers/vhost/net.c
@@ -5,6 +5,7 @@
* virtio-net server in host kernel.
*/
+#include <linux/refcount.h>
#include <linux/compat.h>
#include <linux/eventfd.h>
#include <linux/vhost.h>
@@ -92,7 +93,7 @@ struct vhost_net_ubuf_ref {
* 1: no outstanding ubufs
* >1: outstanding ubufs
*/
- atomic_t refcount;
+ refcount_t refcount;
wait_queue_head_t wait;
struct vhost_virtqueue *vq;
};
@@ -240,7 +241,7 @@ vhost_net_ubuf_alloc(struct vhost_virtqueue *vq, bool zcopy)
ubufs = kmalloc(sizeof(*ubufs), GFP_KERNEL);
if (!ubufs)
return ERR_PTR(-ENOMEM);
- atomic_set(&ubufs->refcount, 1);
+ refcount_set(&ubufs->refcount, 1);
init_waitqueue_head(&ubufs->wait);
ubufs->vq = vq;
return ubufs;
@@ -248,7 +249,8 @@ vhost_net_ubuf_alloc(struct vhost_virtqueue *vq, bool zcopy)
static int vhost_net_ubuf_put(struct vhost_net_ubuf_ref *ubufs)
{
- int r = atomic_sub_return(1, &ubufs->refcount);
+ refcount_dec(&ubufs->refcount);
+ int r = refcount_read(&ubufs->refcount);
if (unlikely(!r))
wake_up(&ubufs->wait);
return r;
@@ -257,7 +259,7 @@ static int vhost_net_ubuf_put(struct vhost_net_ubuf_ref *ubufs)
static void vhost_net_ubuf_put_and_wait(struct vhost_net_ubuf_ref *ubufs)
{
vhost_net_ubuf_put(ubufs);
- wait_event(ubufs->wait, !atomic_read(&ubufs->refcount));
+ wait_event(ubufs->wait, !refcount_read(&ubufs->refcount));
}
static void vhost_net_ubuf_put_wait_and_free(struct vhost_net_ubuf_ref *ubufs)
@@ -909,7 +911,7 @@ static void handle_tx_zerocopy(struct vhost_net *net, struct socket *sock)
ctl.ptr = ubuf;
msg.msg_controllen = sizeof(ctl);
ubufs = nvq->ubufs;
- atomic_inc(&ubufs->refcount);
+ refcount_inc(&ubufs->refcount);
nvq->upend_idx = (nvq->upend_idx + 1) % UIO_MAXIOV;
} else {
msg.msg_control = NULL;
@@ -1384,7 +1386,7 @@ static void vhost_net_flush(struct vhost_net *n)
vhost_net_ubuf_put_and_wait(n->vqs[VHOST_NET_VQ_TX].ubufs);
mutex_lock(&n->vqs[VHOST_NET_VQ_TX].vq.mutex);
n->tx_flush = false;
- atomic_set(&n->vqs[VHOST_NET_VQ_TX].ubufs->refcount, 1);
+ refcount_set(&n->vqs[VHOST_NET_VQ_TX].ubufs->refcount, 1);
mutex_unlock(&n->vqs[VHOST_NET_VQ_TX].vq.mutex);
}
}
--
2.7.4
Hi Xiyu,
Thank you for the patch! Perhaps something to improve:
[auto build test WARNING on vhost/linux-next]
[also build test WARNING on v5.14-rc1 next-20210716]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch]
url: https://github.com/0day-ci/linux/commits/Xiyu-Yang/vhost_net-Convert-from-atomic_t-to-refcount_t-on-vhost_net_ubuf_ref-refcount/20210718-101502
base: https://git.kernel.org/pub/scm/linux/kernel/git/mst/vhost.git linux-next
config: i386-randconfig-a015-20210718 (attached as .config)
compiler: gcc-10 (Ubuntu 10.3.0-1ubuntu1~20.04) 10.3.0
reproduce (this is a W=1 build):
# https://github.com/0day-ci/linux/commit/8aaf246d79e6bb03b71d9a1a13289f919aa34215
git remote add linux-review https://github.com/0day-ci/linux
git fetch --no-tags linux-review Xiyu-Yang/vhost_net-Convert-from-atomic_t-to-refcount_t-on-vhost_net_ubuf_ref-refcount/20210718-101502
git checkout 8aaf246d79e6bb03b71d9a1a13289f919aa34215
# save the attached .config to linux build tree
make W=1 ARCH=i386
If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <[email protected]>
All warnings (new ones prefixed by >>):
drivers/vhost/net.c: In function 'vhost_net_ubuf_put':
>> drivers/vhost/net.c:253:2: warning: ISO C90 forbids mixed declarations and code [-Wdeclaration-after-statement]
253 | int r = refcount_read(&ubufs->refcount);
| ^~~
vim +253 drivers/vhost/net.c
249
250 static int vhost_net_ubuf_put(struct vhost_net_ubuf_ref *ubufs)
251 {
252 refcount_dec(&ubufs->refcount);
> 253 int r = refcount_read(&ubufs->refcount);
254 if (unlikely(!r))
255 wake_up(&ubufs->wait);
256 return r;
257 }
258
---
0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/[email protected]
Hi Xiyu,
Thank you for the patch! Perhaps something to improve:
[auto build test WARNING on vhost/linux-next]
[also build test WARNING on v5.14-rc1 next-20210716]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch]
url: https://github.com/0day-ci/linux/commits/Xiyu-Yang/vhost_net-Convert-from-atomic_t-to-refcount_t-on-vhost_net_ubuf_ref-refcount/20210718-101502
base: https://git.kernel.org/pub/scm/linux/kernel/git/mst/vhost.git linux-next
config: arm64-randconfig-r021-20210718 (attached as .config)
compiler: clang version 13.0.0 (https://github.com/llvm/llvm-project 5d5b08761f944d5b9822d582378333cc4b36a0a7)
reproduce (this is a W=1 build):
wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
chmod +x ~/bin/make.cross
# install arm64 cross compiling tool for clang build
# apt-get install binutils-aarch64-linux-gnu
# https://github.com/0day-ci/linux/commit/8aaf246d79e6bb03b71d9a1a13289f919aa34215
git remote add linux-review https://github.com/0day-ci/linux
git fetch --no-tags linux-review Xiyu-Yang/vhost_net-Convert-from-atomic_t-to-refcount_t-on-vhost_net_ubuf_ref-refcount/20210718-101502
git checkout 8aaf246d79e6bb03b71d9a1a13289f919aa34215
# save the attached .config to linux build tree
COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross ARCH=arm64
If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <[email protected]>
All warnings (new ones prefixed by >>):
>> drivers/vhost/net.c:253:6: warning: ISO C90 forbids mixing declarations and code [-Wdeclaration-after-statement]
int r = refcount_read(&ubufs->refcount);
^
1 warning generated.
vim +253 drivers/vhost/net.c
249
250 static int vhost_net_ubuf_put(struct vhost_net_ubuf_ref *ubufs)
251 {
252 refcount_dec(&ubufs->refcount);
> 253 int r = refcount_read(&ubufs->refcount);
254 if (unlikely(!r))
255 wake_up(&ubufs->wait);
256 return r;
257 }
258
---
0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/[email protected]
On Sat, Jul 17, 2021 at 06:20:30PM +0800, Xiyu Yang wrote:
> refcount_t type and corresponding API can protect refcounters from
> accidental underflow and overflow and further use-after-free situations.
>
> Signed-off-by: Xiyu Yang <[email protected]>
> Signed-off-by: Xin Tan <[email protected]>
Pls resubmit after addressing the build bot comments.
Thanks!
> ---
> drivers/vhost/net.c | 14 ++++++++------
> 1 file changed, 8 insertions(+), 6 deletions(-)
>
> diff --git a/drivers/vhost/net.c b/drivers/vhost/net.c
> index 6414bd5741b8..e23150ca7d4c 100644
> --- a/drivers/vhost/net.c
> +++ b/drivers/vhost/net.c
> @@ -5,6 +5,7 @@
> * virtio-net server in host kernel.
> */
>
> +#include <linux/refcount.h>
> #include <linux/compat.h>
> #include <linux/eventfd.h>
> #include <linux/vhost.h>
> @@ -92,7 +93,7 @@ struct vhost_net_ubuf_ref {
> * 1: no outstanding ubufs
> * >1: outstanding ubufs
> */
> - atomic_t refcount;
> + refcount_t refcount;
> wait_queue_head_t wait;
> struct vhost_virtqueue *vq;
> };
> @@ -240,7 +241,7 @@ vhost_net_ubuf_alloc(struct vhost_virtqueue *vq, bool zcopy)
> ubufs = kmalloc(sizeof(*ubufs), GFP_KERNEL);
> if (!ubufs)
> return ERR_PTR(-ENOMEM);
> - atomic_set(&ubufs->refcount, 1);
> + refcount_set(&ubufs->refcount, 1);
> init_waitqueue_head(&ubufs->wait);
> ubufs->vq = vq;
> return ubufs;
> @@ -248,7 +249,8 @@ vhost_net_ubuf_alloc(struct vhost_virtqueue *vq, bool zcopy)
>
> static int vhost_net_ubuf_put(struct vhost_net_ubuf_ref *ubufs)
> {
> - int r = atomic_sub_return(1, &ubufs->refcount);
> + refcount_dec(&ubufs->refcount);
> + int r = refcount_read(&ubufs->refcount);
> if (unlikely(!r))
> wake_up(&ubufs->wait);
> return r;
> @@ -257,7 +259,7 @@ static int vhost_net_ubuf_put(struct vhost_net_ubuf_ref *ubufs)
> static void vhost_net_ubuf_put_and_wait(struct vhost_net_ubuf_ref *ubufs)
> {
> vhost_net_ubuf_put(ubufs);
> - wait_event(ubufs->wait, !atomic_read(&ubufs->refcount));
> + wait_event(ubufs->wait, !refcount_read(&ubufs->refcount));
> }
>
> static void vhost_net_ubuf_put_wait_and_free(struct vhost_net_ubuf_ref *ubufs)
> @@ -909,7 +911,7 @@ static void handle_tx_zerocopy(struct vhost_net *net, struct socket *sock)
> ctl.ptr = ubuf;
> msg.msg_controllen = sizeof(ctl);
> ubufs = nvq->ubufs;
> - atomic_inc(&ubufs->refcount);
> + refcount_inc(&ubufs->refcount);
> nvq->upend_idx = (nvq->upend_idx + 1) % UIO_MAXIOV;
> } else {
> msg.msg_control = NULL;
> @@ -1384,7 +1386,7 @@ static void vhost_net_flush(struct vhost_net *n)
> vhost_net_ubuf_put_and_wait(n->vqs[VHOST_NET_VQ_TX].ubufs);
> mutex_lock(&n->vqs[VHOST_NET_VQ_TX].vq.mutex);
> n->tx_flush = false;
> - atomic_set(&n->vqs[VHOST_NET_VQ_TX].ubufs->refcount, 1);
> + refcount_set(&n->vqs[VHOST_NET_VQ_TX].ubufs->refcount, 1);
> mutex_unlock(&n->vqs[VHOST_NET_VQ_TX].vq.mutex);
> }
> }
> --
> 2.7.4